Frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD) are two common forms of dementia, both of which present significant problems in clinical diagnosis and patient management. In the early stages of FTLD, many of the symptoms are behavioral, including changes in emotional behavior, social behavior, and personality. These behavioral symptoms have not been well-specified, and thus FTLD often goes unrecognized or misdiagnosed. In the early stages of AD, cognitive changes (e.g, memory loss) are most prominent, but changes in socio-emotional behavior and personality may develop later. As with FTLD, tools for precisely assessing these socio-emotional and personality changes in AD are lacking. We propose to evaluate the utility of applying methods developed in basic behavioral research to achieve a more comprehensive assessment of emotion, social behavior, and personality in these two clinical syndromes. This assessment will measure: (a) actual emotional behavior as it occurs (as opposed to solely relying on retrospective reports); (b) major emotional functions, including emotional reactivity, emotional regulation, and emotional knowledge; (c) major classes of emotion, including negative emotions, positive emotions, and self-conscious emotions; (d) different contexts in which emotions occur, including when the person is alone and responding to wellspecified stimuli and when the person is in meaningful social contexts (e.g., interacting with a loved one); (e) multiple indicators of emotion, including subjective experience, expressive behavior, and autonomic nervous system physiology; (f) changes in emotional functioning that occur over time; and (g) changes in personality. The research addresses four specific aims: (a) to use methods derived from basic behavioral research to evaluate changes in emotional reactivity, emotional regulation, emotional knowledge, and personality in FTLD and AD; (b) to evaluate the relationship that purported genetic markers of FTLD have with emotional behavior and personality in families with a positive history of FTLD; (c) to evaluate relationships between specific regions of brain degeneration and attendant changes in emotional behavior; and (d) to evaluate changes in socio-emotional behavior in FTLD and AD patients by studying dyadic interaction with spouses. Delineating socio-emotional and personality changes in dementia can contribute to more accurate, earlier diagnosis; to identifying important subtypes of these disorders; and to helping us better deal with the profound impact that these disorders have on the lives of patients and their families.